Campylobacter, a common bacteria, was the cause of the illness. It can cause diarrhea, abdominal pain and fever. No deaths were reported, but 26 people were hospitalized.

Samples of the bacteria showed resistance to all antibiotics commonly used to treat the infections, according to the CDC. People with weakened immune symptoms and infants are most at risk.

Out of the 118 people infected, 28 were pet store employees, and 101 people reported contact with a pet store puppy.

The infection was traced back to 25 breeders and eight distributors. The CDC did not identify a source of the infection.

The CDC believes puppies sold through the commercial dog industry were the source of the multistate outbreak.

Officials in four states (Kentucky, Ohio, Pennsylvania, and Wisconsin) visited 20 pet stores and collected antibiotic administration records for 154 puppies. Among 149 puppies with available information, 142 received one or more antibiotic courses before arriving or while at the store.